Rotary positive displacement pumping apparatus



v p 16, 1969 J. o. SIMPKINS ETAL 3,467,019

ROTARY POSITIVE DISPLACEMENT PUMPING APPARATUS Filed Aug. 31, 1967 3 Sheets$heet l P 1969 J. o. SIMPKINS ETAL 3,467,019

ROTARY POSITIVE DISPLACEMENT PUMPING APPARATUS Filed Aug. 31, 1967 3 Sheets-Sheet 2 FIGS Sept. 1969 J. o. SIMPKINS ETAL 3,467,019

ROTARY POSITIVE DISPLACEMENT PUMPING APPARATUS Filed Aug. 31, 1967 3 Sheets-Sheet 5 FIG.4

w no.5

United States Patent US. Cl. 103-117 13 Claims ABSTRACT OF THE DISCLOSURE A rotary flexible vaned impeller pump, the impeller of which is .attached to a hub that slides into the pump chamber on an impeller shaft from an open end of the chamber, the hub also carrying a seal for the other end of the impeller chamber.

This invention relates to rotary pumping apparatus of the type comprising a flexible-vane impeller adapted to be rotated in a cylindrical pump chamber having circumferentially spaced inlet and discharge ports, and means, such as a cam-plate on the interior wall of of the casing, for radially flexing the impeller vanes as they rotate between the ports to provide a pumping action.

In operating such pumping apparatus, the impeller is keyed to a driving shaft projecting into the chamber from one end, and it is necessary to provide sealing means to prevent egress of fluid between the shaft and the opening through which it enters the chamber.

It is an object of the present invention to provide pumping apparatus of the type described which is economical to manufacture, and which is simple to assemble and disassemble for cleaning and maintenance purposes.

The invention consists in pumping apparatus of the type described in which the impeller and sealing means (or at least a part thereof) for preventing egress of fluid from the pump chamber through an impeller drive shaft opening at one end of the chamber are adapted to be inserted into and removed from the chamber as .a unit from its other end, said unit being adapted to slide axially along the drive shaft.

The invention also consists in pumping apparatus of the type described in which a common mounting hub is provided for the impeller and for sealing means (or at least a part thereof) for preventing egress of fluid from the pump chamber through a shaft opening at one end of the chamber the arrangement being such that the impeller and sealing means (or part thereof) may be inserted into or removed from the chamber conjointly from its opposite end on said hub.

The invention will now be described by way of example with reference to the accompanying drawings in which:

FIGURE 1 is a sectional view of a pump close coupled to an electric motor;

FIGURE 2 is a section on line IIII of FIGURE 1;

FIGURE 3 is a section through a pump chamber of alternative design, and

FIGURES 4 and 5 are sectional views of further pumps according to the invention.

In carrying the invention into effect according to one mode by way of an example, a rotary pump as shown in FIGURES 1 and 2 has a body 1 formed internally with a generally cylindrical pumping chamber 2 provided with circumferentially spaced inlet and discharge ports 3 and 4, the chamber being open at one end for insertion of the pump components, a cover plate 5 and gasketing or other sealing means such as an O-ring 6 being provided for closing the open end, and the chamber at its other end leading into a smaller diameter chamber 7 for shaft sealing means, which smaller chamber itself terminates in an end wall 8 of the casing having a central opening 9 for the pump impeller shaft. The casing may have means 11 for close-coupling it to a motor 12 or other driving means in which case the motor or other shaft extension 10 projects through said opening into the pumping chamber.

A flexible-vaned impeller 13, which may be moulded or may be an extrusion of the same length as the pumping chamber, has an internal bore by which the impeller is bonded to a hollow hub 15, which hub is closed at the cover plate end of the impeller and which at the opposite end, has a tubular sleeve portion 16 projecting beyond the impeller by an amount at least equal to the length of the sealing chamber 7. The bore of the hub member is dimensioned to be a sliding fit on the driving shaft. The impeller bore and outer hub surface to which it is bonded may be circular in section, but to reduce the shear load between these components, a non-circular shape such as hexagonal is preferred.

On its tubular portion projecting from the impeller, the hub carries sealing means comprising a resilient seal 17 remote from the impeller adapted in operation to press against the end wall of the seal chamber and being a tight fit around the hub, and a helical thrust spring 18 positioned between end plates 19, the spring acting between the impeller and the seal to urge the latter away from the impeller. A split-ring 20 may be provided behind the seal to hold the sealing means on the hub member during extraction.

The end wall of the sealing chamber against which the seal abuts may itself be machined to provide in conjunction with the seal an adequate sealing effect, or alternatively, this wall may be machined to receive, and retain, insert against which the seal abuts to provide this effect.

To assemble the pump, with the end cover plate re moved, and assuming that the pump body is close-coupled to a motor, the unitary structure comprising hub member impeller and sealing means, is merely slid into the chamber from its open end along the driving shaft, and the coverplate is then attached to the open end of the chamber with interposed gasketing or O-ring.

When assembled, the impeller occupies the entire length of the pumping chamber, and the hub extension extends through the sealing means chamber and projects into the shaft opening in the chamber end wall with small clearance. The sealing means is dimensioned such that its spring presses the seal against the end wall of the sealing chamber, and this together with its tight peripheral fit on the hub extension prevents egress of fluid through said clearance. The seal 17 is of smaller diameter than the sealing chamber 7, so that in dissembling the pump, when the cover plate is removed, the impeller, hub and sealing means can be readily removed as a unit.

Any suitable drive means such as conventional keying can be used between the shaft and the hub, but in one convenient arrangement, the hub carries a cross-pin 21 adapted to be accommodated in a slot at the end of the shaft.

In an alternative form of the invention, as shown in FIGURE 4 the axial length of the sealing chamber 7a is reduced, and the sealing means in the form described above is partially accommodated in an annular recess 21 in the hub member 15a under the impeller 13a, the hub member in this case having a larger outside dimension than in the previously described arrangement. In a further alternative, as shown in FIGURE 5 the sealing means chamber is entirely eliminated and the sealing means is accommodated completely in an anular recess 21b in the hub 15b under the impeller 13b.

The invention is applicable to pumps in which the cam member for flexing the impeller vanes is formed integrally with the pumping chamber wall as shown in FIGURE 2 or to pumps where the cam is removable. According to another aspect of the invention, a removable cam member 24 (FIGURE 3) for a pump of the type described is provided on its outer surface with a projecting lug 25 adapted to project through an opening in the pump-ing chamber wall, frictional means, such as a resilient O-ring 26 on the lug, being provided for frictionally retaining same in the opening. To insert the cam the lug is pressed up into the opening so that the O-ring frictionally engages therewith, with the free end of the lug projecting from the casing exterior, and to remove the cam, the exteriorly projecting portion of the lug is merely depressed.

According to a still further feature of the invention there may be provided a low friction thrust pad 27 between the impeller and the cover plate (see FIGURES 1 and 4), to reduce friction between the impeller and the cover plate produced by the spring of the sealing means. The pad may, for example, he a low friction synthetic plastics material and can be recessed into the end of the impeller or into the cover plate.

We claim:

1. Rotary pumping apparatus comprising housing defining a generally cylindrical pump chamber, means forming circumferentially spaced inlet and outlet ports leading into said chamber, a flexible vane impeller adapted to be rotated within the chamber, means for flexing the impeller vanes between said ports to provide a pumping action, means defining an opening at one end of said chamber for an impeller drive shaft, and sealing means for preventing egress of liquid from said chamber through said opening characterised in that said impeller and said sealing means are adapted to be inserted into and removed from said chamber as a unit from the other end of said chamber by axial sliding of said unit along an impeller drive shaft.

2. Rotary pumping apparatus comprising housing defining a generally cylindrical pump chamber, means forming circumferentially spaced inlet and outlet ports leading into said chamber, a flexible vane impeller adapted to be rotated within the chamber, means for flexing the impeller vanes between said ports to provide a pumping action, means defining an opening at one end of said chamber for an impeller drive shaft, an impeller hub and sealing means for preventing egress of liquid from the chamber through said opening around the shaft characterised in that the impeller and sealing means are carried by the hub for insertion into and removal from the pump chamber as a unit from the opposite end of the chamber by sliding of the hub along the impeller drive shaft.

3. The apparatus of claim 2 characterised in that said hub has an extension portion adapted to carry the sealing means said extension portion being dimensioned to extend through said shaft opening.

4. The apparatus of claim 2 characterised by means defining an ante-chamber off the pump chamber said antechamber being adapted to locate the sealing means.

5. The apparatus of claim 4 characterised in that the sealing means is of slightly smaller diameter than the ante-chamber to facilitate removal of the sealing means.

6. The apparatus of claim 2 characterised by means defining an ante-chamber leading off the pump chamber and means defining an annular recess under the impeller, the sealing means fitting partly in said ante-chamber and partly in said recess.

7. The apparatus of claim 2 characterised by means defining an annular recess under said impeller for accommodation of the sealing means.

8. The apparatus of claim 7 characterised in that said annular recess is formed in said hub.

8. The apparatus of claim 7 characterised in that said annular recess is formed in said hub.

9. The apparatus of claim 2 characterised in that the sealing means includes a resilient seal and a coil spring adapted to press the seal against a wall defining said shaft opening.

10. The apparatus of claim 2 characterised by a cover plate for the opposite end of the pump chamber and antifriction means for reducing friction between said impeller and said cover plate.

11. The apparatus of claim 2 characterised by a portion of the pump chamber wall being machined to provide the means for flexing the impeller vanes between the ports.

12. The apparatus of claim 2 characterised by a displaceable cam adapted to fit against the pump chamber wall to flex the impeller vanes between the parts.

13. The apparatus of claim 12 characterised by a lug formed on said cam and means defining an opening in the pump chamber wall through which opening the lug projects the lug having a friction fit in said opening.

References Cited UNITED STATES PATENTS 2,648,287 8/1953 Thoren et a1. 2,836,877 6/ 1958 Hannahan. 2,853,021 9/ 1958 Doble. 2,858,769 11/1958 Doble. 2,881,710 4/ 1959 McLean. 2,971,469 2/ 1961 McLean. 2,976,811 3/ 1961 Sully l03l4() 3,240,154 3/1966 Robbins 103-l40 3,303,791 2/1967 Doble.

FOREIGN PATENTS 1,035,009 7/1966 Great Britain.

WILLIAM L. FREEH, 'Primary Examiner WILBUR I. GOODLIN, Assistant Examiner US. Cl. X.R. 

